It also helps to drop the temperature inside the cylinders by interducing burned up gases when the cylinders reach high temperature....as @Barry said they can be blocked and pcm can be programmed to delete the system itself.. engines smaller in size and higher in displacement have been running without this system and they didn't have any problem so that engine shouldn't be any different....
Yes, you can make up blanking plates and block everything off. Have a look on eBay, there are blanking kits available for a lot of cars, search EGR delete and your particular model. The EML might come on but any good tuning shop will be able to edit the ECU and take the EGR out of the main program.
A faulty EGR valve can cause overheating. The associated pipework can block up too and also cause overheating.
It’s a nasty system and the main purpose is to get cars past emissions regulations. Look at it this way, your engine burns fuel then tries to get rid of the smoke out the exhaust. The EGR then puts some of that smoke back into the engine to try to burn it again. Which means you could be pumping carbon, oil and all other sorts of nasty crap back into your engine again, which can never be a good thing.
While not strictly legal, often the best thing to do, especially on Diesel engines, is to blank off all the EGR components, and if it’s a newer car, have it mapped out of the ECU.